基于微重力条件下的导热控制微分方程,采用焓法对热管吸热器相变材料容器进行了二维数值建模与仿真,在同时考虑空穴和相变的情况下,对微重力条件下蓄热单元相变传热进行了模拟计算,分析了空穴率对蓄热容器内部的温度场和热性能的影响,并将计算结果同美国航空航天局(NASA)方案热管吸热器蓄热单元相变传热计算结果进行了比较,验证了文中微重力条件下计算模型的合理性与准确性。研究结果表明:空穴影响着蓄热单元相变的进程,空穴的存在增加了容器内部的温度梯度,使得容器的蓄热能力降低;由于热管径向温差较小,热管壁温在相变材料熔点附近变化较小,从而在一定程度上能缓解热斑和热松脱现象。
High temperature heat pipe receivers are commonly used as a core component of space solar dynamic power system. On the base of heat conduction governing differential equation under microgravity, two-dimensional numerical analysis of PCM container was conducted by a enthalpy method.With both void cavity and phase change considered,thermal performance of heat pipe receiver was analyzed.Numerical results were compared with NASA results.The accuracy of calculation model under gravity was verified.The results indicate that void cavity influences the process of phase change.The void cavity reduces the utility and thermal storage ability of PCM.The temperature gradient of PCM zone is very significant because of the void cavity. The PCM contained in the integrated heat pipe performs the averaging function of the heat loads.Normal working of wick ensures the uniformity of heat pipe,thus heat pipe receiver alleviates thermal spot and thermal ratcheting.